Process of making metal powder.



w. c. MOORE.

PROCESS OF MAKING METAL POWDER.

' APPLICATION FILED JULY 29, I915- Patented Jan. 22, 1918.

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WILL: .MD on: BY 4Q ad 4 TTORNEY WITNESS jVTW UNITED STATES PATENTOFFICE.

WILLIAM G. moons, or LAKEWOOD, omo, ASSIIGNOR, :BY' MESNE ASSIGNMENTS,'ro

' NATIONAL CARBON COMPANY, INC., A CORPORATION OF NEW YORK. I

PROCESS OF MAKING 'METAL POWDER.

Specification of Letters Patent.

Patented J an.22 ,1918.

Application filed July 29, 1915. Serial No. 42,527.

To all whom it may concern:

Be it known that I, WILLIAM C. MOORE, a citizen of the United States,residing at Lakewood, in the county of Cuyahoga and State of Ohio, haveinvented a certain new and useful Improvement in Processes of- MakingMetal Powder, of which'the following is a full, clear, and exactdescription.

My invention relates to the making of metal powders and also to currentcollecting brushes made from the same.

My invention is an improvement over prior processes in that relativelysimple ap-' paratus is required and the metal powder is obtained in asubstantially pure condition. The advantages of the improvement will beapparent on reading the appended description, reference being also hadto the drawcathode surface were used, the copper would I late out in asmooth, adherent coating on the cathode when current is sent through thecell. Desiring to secure the metal in a loose, powdery condition, Ifollow an opposite course and send through a current of high density inregard to cathode surface- In view of this, it is advisable to use acopper wire-as cathode, while the anode may be a heavy copper plate. I

When a current of. high density is used,

copper is deposited out on the cathode in the form of fine powder whichloosely collects thereon, as indicated at 5' on the drawing.

The powder must not be allowed to accumulate on the cathode to any greatextent for it naturally increases the surface of the cathode which. atthe same time cuts down the amperes per square inch cathode surface.

If low current density per square inch of somewhere near constant inorder to have the deposit of uniform character and therefore some manualor automatic arrangement is used to tap the cathode gently at shortintervals. I have found that the powder should be removed at least every5 or 10 minutes by tapping the cathode.

.To remove the powder automatically, a clock, motor or other arrangementcan be used, andI have diagrammatically illustrated one such form in thedrawings. An electric motor 6 is geared through the requisite number ofgears to a wheel 7 having a pin 8 which rises under a portion 9 of atappet 10 and raises the latter to the position shown in dotted lines inthe figure, where the in will clear the portion 9 and the tappet willspring downward under its own resilience to hit the cathode and removethe powder. This powder collects in a pile 11 at the bottom of thecontainer and can be removed periodically in any manner.

,When the powder is fresh from the electrolyte it is in a very purecondition on account of the method of preparation, but if allowed tostand after washing out the copper sulfate solution, it will more orless change over into copper oxid. Drying in cacao, after washing outthe copper sulfate solution, reduces this action, but it does noteliminate the difficulty to a sufficient extent to permit the powder tobe used in making brushes. i

I have found that oxidation can be prevented by washing the powder witha liquid containing such materials as glucose, tannin, or othercolloids, and thereby cause a precipitation of the colloids as a thincoating on the metal particles due to the action of the copper sulfateelectrolyte. While glucose solution acts very satisfactorily, I preferto use a tannin solution on account of its low cost. One way to carryout this step is to wash the powder fresh from the electrolyte in. a teamade by steeping maple, oak

or other sawdust in waterf *When the powder is washed in this solutionthe-tanning is molded under high pressure into the desired form. Themolded article is then baked at a high temperature to cause the metalparticles to adhere together and form a solid article. Brushes made inthis way are strong and have good lubricating and conbut still highercurrent densities may he used.

The concentration of the electrolyte also plays an important part in theprocess. The

more concentrated the electrolyte, the coarser the powder is. l havefound that a .8 normal solution of copper sulfate is the mostsatisfactory for obtaining the right quality of copper powder for,brushes, though different concentrations can be used, especially whenarticles other than 'metallic brushes are to be made from the powder,

As a further detail of the process I have found that it is advisable toarrange the apparatus so that the oxid, which is formed in smallquantities at the anode, will not drop into and contaminate the copperpowder. There are various ways of doing this, one of which is by placinga nonconducting partition 12 through the center of the lower part of thecontainer, so that the copper powder will not settle under the anode inpositionto be contaminated with the oxid. Another very efiicient way ofsolving the problem is to inclose the copper anode in a cloth envelop orscreen 13 which will allow the electrolyte to readily percolate throughnaeaosa it, but which will prevent the oxid from falling to the bottomof the cell.

While T have described my invention with particular reference to theobtaining of copperpowder, it is nevertheless apparentithat .the processcan be used in making other metal powders. For instance, I have formedzinc powder by electrolyzing zinc sulfate solution, iron powder byelectrolyzing ferrous sulfate solution,

Having described my invention, what l claim is 1. The process of makingmetal powder, which consists in forming metal sponge in an electrolyteand placing the metal sponge ticles with a protective covering toprevent oxidation and then drying the coated particles.

3. The process of making a metal powder, which consists in electrolyzinga solution of a salt of the metal to form spongy metal on the cathode,removing the said metal, washing it free of electrolyte in a colloidalsolution and then drying the metal powder.

4. The process of making a metal powder, which consists in electrolyzinga solution of a salt of the metal to form spongy metal on the cathode,removing the said metal, Washing it free of electrolyte in a colloidalsolu tion and drying it in 'vacuo.

In testimony whereof, l hereunto afix my signature.

WILLIAM C, MOGRE.

